Kettledrum

ABSTRACT

A kettledrum comprises a hollow, substantially hemispherical body, a hoop supporting a taut head over the open end of the body, a counterhoop in operative engagement with the hoop, and head tensioning means interengaging the body and counterhoop. The tensioning means comprise a plurality of pairs of spaced thrust bearings and brackets extending radially from the body at peripheral intervals. First clamp means associated with each pair and flexible drive means interconnecting all of the pairs adjust the tension of the head uniformly across its surface. Second clamp means associated with each first clamp means selectively adjusts the tension of the head in the area immediately adjacent. The drum is supported on the brackets, certain of which are freely supported interconnecting all of the pairs adjust the tension of the head uniformly across its surface. Second clamp means associated with each first clamp means selectively adjusts the tension of the head in the area immediately adjacent. The drum is supported on the brackets, certain of which are freely supported on associated leg members. The resulting drum suspension imparts a clear, unmuffled tone to the drum.

United States Patent Kregal [54] KETTLEDRUM [72] Inventor: Jesse N. Kregal, 6244 Washington Ct.,

Lake Grove, Oreg. 97034 [22] Filed: Dec. 12, 1969 [21] Appl. No.: 884,455

[52] U.S.C1. ..84/419, 84/421 [51] Int.Cl. ..G10d l3/04,G10d 13/02 [58] FieldofSeurcL. .....84l419,4l1.1,411,421,4l3

[56] References Cited UNITED STATES PATENTS 1,391,437 9/1921 Wiedoeft ..84/419 2,173,443 9/1939 Schuman ....84/411 Primary Examiner-Richard B. Wilkinson 1 1 Mar. 7, 1972 Assistant Examiner-John F. Gonzales Attorney-Eugene D. Farley ABSTRACT A kettledrum comprises a hollow, substantially hemispherical body, a hoop supporting a taut head over the open end of the body, a counterhoop in operative engagement with the hoop, and head tensioning means interengaging the body and counterhoop. The tensioning means comprise a plurality of pairs of spaced thrust bearings and brackets extending radially from the body at peripheral intervals. First clamp means associated with each pair and flexible drive means interconnecting all of the pairs adjust the tension of the head uniformly across its surface. Second clamp means associated with each first clamp means selectively adjusts the tension of the head in the area immediately adjacent. The drum is supported on the brackets, certain of which are freely supported interconnecting all of the pairs adjust the tension of the head uniformly across its surface. Second clamp means associated with each first clamp means selectively adjusts the tension of the head in the area immediately adjacent. The drum is supported on the brackets, certain of which are freely supported on associated leg members. The resulting drum suspension imparts a clear, unmuffled tone to the drum.

16 Chins, 8 Drawing Figures PATENTEUMAR 7 I972 3, 646 843 SHEET 1 OF 2 'Jesse N. Kregol INVEN'TOFZ PATENTEDMAR 71912 V 3, 646.843

sum 2 [IF 2 v (16556 N. Kregczl v B IN ENTOR KETTLEDRUM This invention relates to kettledrums, also known as timpani. In particular, the present invention relates to kettledrums having an improved tuning mechanism and an improved suspension.

Kettledrums or timpani are unlike most other drums in that they have very definite pitch. The drumhead tension varies the pitch and gives each drum its pitch range. It is important that the drum be provided with tuning means so that the artist can change the pitch easily and accurately as required by the composition he is playing.

Two basic techniques are employed to vary the pitch of the kettledrums of the prior art. One is the provision of foot pedals with associated rods and levers which tension a plurality of posts evenly distributed around the circumference of the drum, and accordingly tension the head.

The second type is a hand-operated tuning attachment in which tension posts mounted on the drum are linked together with chain and sprocket, or cable and pulley.

Both categories of kettledrum tuning devices have been seriously deficient in providing accurate tuning and facile adjustment. It accordingly is the general purpose of the present invention to provide a kettledrum of the chain and sprocket type having an integral tuning mechanism which makes it possible to tune the drum accurately, easily and rapidly and which is characterized by the following additional advantages:

The tuning attachment itself freely suspends the drum on its legs providing a suspended kettle so that a pure, unmuffled tone is obtained. This enhances the purity of the sound produced by the instrument, and accordingly makes possible more accurate tuning.

The entire drum may be tuned to a new pitch or, where demanded by such factors as variations in drumhead texture, a selected area of the drumhead may be tuned separately to impart a uniform tone quality to the instrument. I

The tuning mechanism is entirely below the plane of the drumhead. This allows the freest and most uninhibited movement by the artist and improves his performance correspondingly.

The tuning controls are readily accessible.

. An accurate and easily read gauge is associated with the tuning mechanism so that the drum pitch is read easily, and reproducible tuning is possible.

A complete range of tuning is available, without mechanical limitations.

The tuning mechanism operates freely, does not fail at awkward moments and controls the pitch positively and accurately over a long service life.

The manner in which the foregoing and other objects of this invention are accomplished will be apparent from the accompanying specification and claims considered together with the drawings, wherein:

FIG. 1 is a view in perspective of a kettledrum having the herein described tuning mechanism applied thereto;

FIG. 2 is a fragmentary plan view of the kettledrum;

FIG. 3 is a fragmentary plan view of a chain tensioning device applied to the kettledrum;

FIGS. 4 and 5 are sectional views taken along lines 4-4 of FIG. 3 and 5-5 of FIG. 2; respectively;

FIG. 6 is a detail view in elevation of the tuning mechanism associated with the drum; and

FIGS. 7 and 8 are longitudinal and transverse sectional views taken along'lines 77 and 8-8, respectively of FIG. 6.

Generally stated, the kettledrum of timpano of my invention comprises a hollow, substantially hemispherical body, a hoop supporting a taut head over the open end of the body, a counterhoop in operative engagement with the hoop and head ten- 1 drum on the legs and imparts to it a desired clear, unmuffled tone.

Considering the foregoing in greater detail and with particular reference to the drawings:

The kettledrum assembly is shown generally in FIG. 1. It includes a drum, indicated generally at 10, supported on a stand, indicated generally at 12.

The drum 10 includes a kettle or body 14 which is hemispherical in shape and open at its upper end. Its upper margin is reversely bent to form a rounded shoulder across which is stretched drumhead 16. This preferably is made of rawhide, although it also may be made of plastic. The margin of the drumhead is secured to a hoop 18 of larger diameter than the diameter of the drum. The hoop in turn is retained in the usual manner by means of a counterhoop 20.

A plurality of tuning units are secured to the drum at spaced peripheral intervals. These extend radially and are indicated generally at 22. It is by means of these units that the tension of the head, and hence the drum pitch, are adjusted.

The construction, manner of mounting and mode of operation of the tuning units is shown in detail in FIGS. 6, 7 and 8.

In essence, each tuning unit comprises general clamping means for adjusting the tension of the entire head area, with associated selective clamping means for adjusting the tension of the head area immediately adjacent the particular tuning unit.

Each tuning unit includes a base 26 riveted or otherwise fixed to the exterior surface of counter hoop 20. The base supports a thrust bearing 28 having an upper recess 30 and a central opening 32. Cooperating with thrust bearing 28 is a bracket 34. The bracket extends radially from the drum body a spaced distance below the thrust bearing, with which it is aligned vertically. It is fixed to the drum body, reinforced by plate 37 by means such as rivets 38.

The bracket preferably is a U-shaped member including a base 40 and a pair of radially extending arms 42 spaced from and parallel to each other. The outer ends of the arms have recesses 44 forming inverted hooks. The lower edge surfaces 46 of the arms provide support and bearing surfaces by means of which the drum is suspended, as will appear hereinafter.

The clamping assembly mounted in each registering pair of thrust bearings 28 and brackets 34 includes a central shaft 50. The shaft has a threaded upper end 52 and a threaded lower end 54. The threads of these two ends are slow and fast for local and general drumhead tensioning, respectively. General tensioning, and hence tuning, thus may be done rapidly, as is necessary during the performance of a given musical number.

The central portion of the shaft is fonned with a longitudinal keyway 56.

Shaft 50 has an overall length such that it extends substantially above thrust bearing 28 and below bracket 34. Its central portion is received in a sleeve 58 having a longitudinally extending key 60 by means of which the sleeve and shaft are coupled together so that they rotate as a single unit. The sleeve slides freely on the shaft in a longitudinal direction within the limits of keyway 56.

Sleeve 58 rotates freely in bearing 28 and is journaled in a ball bearing 62 to permit easy adjustment under working loads.

The upper end of the sleeve is formed with an integral thrust bearing head (hex nut) 64. This is the element by means of which torque is applied to the sleeve and shaft. Its upper surface is formed with a recess 66 communicating with sleeve 58. Its undersurface bears against roller bearing 62 supported on a levelling washer 63 which in turn bears against thrust bearing 28. This assembly is the one by means of which overall tuning of the kettledrum is obtained.

To this end a sprocket 68 also is mounted on sleeve 58 by means of setscrew 70. Flexible interconnecting means such as chain 72 engages the sprockets of all of the assemblies. Hence by rotation of any one of sleeves 58, all of the units may be adjusted in unison.

The desired adjustment is'obtained by mounting on lower threaded section 54 of each shaft a bracket engaging member 74. In the illustrated form of the invention this comprises a cylindrical nut threaded onto the lower end of the shaft and received in hook-forming recesses 44 of bracket 34. Tightening and loosening bearing head 64 applies and releases clamping pressure on counterhoop 20, and hence on drumhead l6.

Selective tuning of the drumhead in the area immediately adjacent each tuning unit is achieved by including in the tuning unit a second bearing head 76. This may comprise a hex nut threaded on the upper end 52 of shaft 50. Its under surface bears against the bottom surface of the recess formed in head 64.

Accordingly tightening and releasing bearing head 76 applies and releases clamping pressure on the drumheadin the area immediately adjacent the tuning unit without involving the remaining area of the drumhead. This is the case since head 76 can be tightened down or released on the fine threads of shaft upper end 52 without activating sprocket 68 and chain 72. The inertia of these elements and associated clamping assembly is sufficient to inhibit their movement while torquing force is applied to head 76.

A chain tightening unit 24 is provided for adjusting the. tension of chain 72 as required to keep the chain taut and prevent slippage. The construction of this unit is shown in FIGS. 3 and 4.

The unit comprises a base 78 riveted or otherwise fixed to counterhoop 20. The base supports a bracket 80 which extends radially outwardly in the plane of chain 72.

The bracket is provided with a radial slot 82 which acts as a slide. A slide block 84 moves freely in the slide. It is adjusted by means of a screw 86 which extends the length of the bracket and slide block.

Block 84 supports a vertical shaft 88, the ends of which are threaded and mount retaining nuts 90 and washers 92.

An idler sprocket 94 is mounted for free rotation on the shaft. It is spaced apart from block 84 by means of a washer 96. Accordingly adjustment of screw 86 shifts the position of idler sprocket 94, as required to adjust the tension on chain 72 engaged by the sprocket.

Indicating means are provided for indicating the pitch of the kettledrum in various conditions of tuning. Its construction and manner of mounting are illustrated in FIGS. 2 and 5.

In providing the pitch indicator, advantage is taken of the fact that the tightness of drumhead 16, and hence the pitch of the drum, are directly related to the displacement of chain 72.

Accordingly a calibrated plate 100 is placed adjacent a stretch of chain 72, parallel thereto. The plate is suitably supported, as by means of an integral spring clip 102 which engages the bottom margin of counterhoop 20. A cooperating pointer 104 is fastened to chain 72 by means of a clip 106. Plate 100 is calibrated in units such that as pointer 104 moves with chain 72, it indicates the pitch of the drum in the assigned units.

It is a further feature of the invention that the same means which are employed to tune the kettledrum may be employed to support it in a freely suspended condition which imparts to it a superior and purer tone quality. The resulting purity of sound in turn makes it possible to tune the drum with a higher degree of accuracy. The drum-supporting elements are indicated in FIGS. 1, 6 and 7.

As shown in FIG. 1, the drum is supported in a stand, in dicated generally at 12. The stand includes a plurality of legs 110 suitably braced for separation by links 112;

Legs 110 are telescoping. Each mounts an extension segment 114 which may be maintained releasably in its predetermined degree of extension by means of a thumbscrew 116.

Leg segment 114 has a cross section such that it may be inserted between arms 42 0f the associated bracket 34. A cross pin 118 mounted on the end of the leg segment bears against the undersurfaces 46 of the arms. I

As is particularly evident in FIG. 7, this provides a support on which the drum hangs freely. This is in direct and desirable contrast to one conventional mode of mounting the drum in which thelatter is mounted on a tripod in direct engagement with the drum'kettle, a situation which results in muffling of the drum tone.

OPERATION To operate the herein described kettledrum, there is provided a wrench 122, FIG. 7. The wrench includes a body 122 having on oneend a first head 124, and on the other end a crossbar 126 mounting a second head 128.

Wrench head 124 is dimensioned to engage thrust bearing head 64. To permit a running adjustment, the wrench usually is left in position while the drum is being played. A thumbscrew then is used to secure the wrench to the head and thus prevent rattling of the assembly.

Turning the wrench in its mounted position exerts. or releases pressure on drumhead 16 through the agency of the clamp comprising sleeve 58 interlocked shaft 50, counterhoop 20 which bears against the drumhead, and bracket engaging cylindrical nut 74 which bears against bracket 34. This effect is transmitted uniformly to all of the companion units through the agency of sprockets 68 and chain 72.

When it it is desired to tune an individual selected area of the drum head the adjacent tuning unit is selected, and wrench head 128 applied to nut 76. This applies or releases clamping pressure to the area concerned only. The companion tuning units are not involved because of the inertia of the system. Contributing to this effect is the fine thread-coarse thread relationship of threaded ends 52, 54 of shaft 50.

Wrench head 128 also may be used to adjust the tension of chain 72 by applying it to the head of adjustment screw 86, which is a component of chain tensioning unit 24.

Having thus described my invention in preferred embodiments, I claim:

1. A kettledrum comprising a. a hollow substantially hemispherical body,

b. hoop means supporting a taut head over the open end of the body,

c. counterhoop means in operative engagement with the hoop means, and

d. head tensioning means interengaging the body and the counterhoop means and comprising:

1. a plurality of thrust bearings mounted radially at spaced peripheral intervals on the counterhoop means,

2. a plurality of brackets secured radially at spaced peripheral intervals to the drum'body, in substantially vertical registration with the thrust bearings,

3. a plurality of adjustable clamp assemblies interconnecting the bearings and brackets, each clamp assembly comprising a. a shaft extending through one of the aligned bearing and bracket pairs, I

b. a sleeve rota'tably and slidably mounted in the bearing, receiving and interlocked with the shaft,

0. a first thrust bearing head integral with the upper end of the sleeve, bearing against the thrust bearing,

d. flexible drive means interconnecting the sleeves of all of the clamp members,

e. bracket engaging means on the lower end of the shaft, v

f. the sleeve and shaft being rotatable together,

g. and the flexible drive means transmitting the torque to the shafts of all of the clamp assemblies, thereby adjusting the pressure applied to the bracket engaging means and correspondingly tensioning the drumhead,

h. a second thrust bearing head on the upper end of the shaft, bearing against the first thrust bearing head and operable to adjust selectively the clamping pressure applied to the drumhead in the area immediately adjacent the clamping assembly.

2. The kettledrum of claim 1 wherein the upper surfaces of the thrust bearing members are recessed and receive bearings joumaling the sleeve. j

3. The kettledrum of claim 1 wherein the brackets comprise a pair of inverted hook-shaped arms and the bracket engaging means comprises a rod receivable in the hook portions of the arms.

4. The kettledrum of claim '1 wherein the sleeve and shaft are keyed together. I

5. The kettledrum of claim 1 wherein the drive means comprise sprockets fixed one to each sleeve and a continuous chain engaging all of the sprockets. v

6. The kettledrum of claim 1 wherein the first thrust bearing head comprises a hollow nut integral with the sleeve and the second thrust bearing head comprises a nut threaded on the shaft and received in a recess in the first thrust bearing head.

7. The kettledrum of claim 1 including tensioning means associated with the flexible'drive means, the tensioning means comprising a radially slotted block secured to the peripheral surface of the body, a slide mounted in the slot, screw means threaded through the bracket and block for adjusting the position of the block in the slide, a vertical shaft mounted on the block and an idler wheel mounted for free rotation on the shaft and engaging the flexible drive means.

8. The kettledrum of claim 1 including a calibrated position scale secured to the body parallel to the flexible drive means and adjacent thereto and pointer means fixed to the flexible drive means in operative position relative to the scale.

9. The kettledrum of claim I wherein selected ones of the brackets are provided with support surfaces and including drum support legs engaging such surfaces, thereby freely supporting the drum.

10. The kettledrum of claim 9 wherein the bracket comprises a pair of parallel spaced-apart arms, the undersurfaces of which provide the support surfaces and wherein the leg is insertable between the arms and provided with a cross pin engaging the support surfaces thereof.

11. The kettledrum of claim 1 wherein the upper and lower ends of the shaft have slow-pitched and fast-pitched threads, respectively, and wherein the second thrust bearing head comprises a nut threaded on the upper end of the shaft and the bracket engaging means comprises a nut threaded on the lower end of the shaft.

12. A kettledrum comprising a. a hollow substantially hemispherical body,

b. hoop means supporting a taut head over the open end of the body,

c. counterhoop means in operative engagement with the hoop means,

d. head tensioning means interengaging the body and counterhoop means, and

e. drum support means comprising 1. a plurality of radially extending brackets mounted on the body, each having a bearing support surface, and

2. a plurality of legs, each engaging the bearing support surface of a selected one of the brackets, thereby freely suspending the drum on the legs.

13. The kettledrum of claim 12 wherein each bracket comprises a pair of parallel spaced arms receiving between them the upper end of the associated leg, and wherein the leg is provided with a cross pin engaging and supporting the arm in bearing rela,ion.

14. A kettledrum comprising a. a hollow, substantially hemispherical body,

b. hoop means supporting a taut head over the open end of the body,

c. counterhoop means in operative engagement with the hoop means, an;

d. head tensioning means interengaging the body and the counterhoop means and comprising:

1. a plurality of thrust bearing members mounted radially at spaced peripheral intervals on the counterhoop means,

2. a plurality of bracket memberssecured radially at I. spacedperipheral intervals to the drum body, in sub stantially vertical registration with the thrust bearing I different speed,

b, first adjusting means operatively engaging one threaded end of the shaft with one of the associated bearing and bracket members,

c. second adjusting means operatively engaging the other threaded end of the shaft with the other of the associated bearing and bracket members,

d. whereby relative rotation of the shaft and first adjusting means effects movement of the associated bearing and bracket members toward and away from each other at one predetermined rate and relative rotation of the shaft and second adjusting means effects movement of the associated bearing and bracket members toward and away from each other at a different predetermined rate, and

e. flexible connecting means interconnecting the plurality of adjusting means associated with the faster threads, whereby adjustment of clamping pressure by one of said adjusting means equally adjusts the clamping pressure applied by the remaining ones of said adjusting means.

15. The kettledrum of claim 14 wherein the second adjusting means comprises a threaded nut on the slower thread of the shaft and engaging the sleeve, and the flexible connecting means is secured to the sleeve,

. whereby rotation of the plurality of sleeves and shafts effects simultaneous movement of the associated bearing and bracket members toward and away from each other at a predetermined rate and rotation of each second adjusting nut relative to its associated shaft effects movement of the associated bearing and bracket members toward and away from each other at a slower rate.

16. A kettledrum comprising a hollow substantially hemispherical body,

hoop means supporting a taut head over the open end of the body,

counterhoop means in operative engagement with the hoop means, and

head tensioning means interengaging the body and the counterhoop means and comprising:

i. a plurality of thrust bearing members mounted radially at spaced peripheral intervals on the counterhoop means,

2. a plurality of bracket members secured radially at spaced peripheral intervals to the drum body, in substantially vertical registration, with the thrust bearing members,

3. a plurality of adjustable clamp assemblies interconnecting the bearing and bracket members, each clamp assembly comprising a. first and second clamp members interconnected for simultaneous rotation and for relative longitudinal. movement,

b. adjustment means interengaging the first and second clampmembers for adjusting one longitudinally relative to the other,

c. means interengaging the first and second clamp members one with its associated bearing member and the other with its ;ssociated bracket member for rotation rela tive thereto to move the bearing and bracket members toward and away from each other,

and

d. flexible connectin said bearingengaging clamp members, whereby adg means interconnecting each of 

1. A kettledrum comprising a. a hollow substantially hemispherical body, b. hoop means supporting a taut head over the open end of the body, c. counterhoop means in operative engagement with the hoop means, and d. head tensioning means interengaging the body and the counterhoop means aNd comprising:
 1. a plurality of thrust bearings mounted radially at spaced peripheral intervals on the counterhoop means,
 2. a plurality of brackets secured radially at spaced peripheral intervals to the drum body, in substantially vertical registration with the thrust bearings,
 3. a plurality of adjustable clamp assemblies interconnecting the bearings and brackets, each clamp assembly comprising a. a shaft extending through one of the aligned bearing and bracket pairs, b. a sleeve rotatably and slidably mounted in the bearing, receiving and interlocked with the shaft, c. a first thrust bearing head integral with the upper end of the sleeve, bearing against the thrust bearing, d. flexible drive means interconnecting the sleeves of all of the clamp members, e. bracket engaging means on the lower end of the shaft, f. the sleeve and shaft being rotatable together, g. and the flexible drive means transmitting the torque to the shafts of all of the clamp assemblies, thereby adjusting the pressure applied to the bracket engaging means and correspondingly tensioning the drumhead, h. a second thrust bearing head on the upper end of the shaft, bearing against the first thrust bearing head and operable to adjust selectively the clamping pressure applied to the drumhead in the area immediately adjacent the clamping assembly.
 2. a plurality of brackets secured radially at spaced peripheral intervals to the drum body, in substantially vertical registration with the thrust bearings,
 2. a plurality of legs, each engaging the bearing support surface of a selected one of the brackets, thereby freely suspending the drum on the legs.
 2. a plurality of bracket members secured radially at spaced peripheral intervals to the drum body, in substantially vertical registration with the thrust bearing members,
 2. The kettledrum of claim 1 wherein the upper surfaces of the thrust bearing members are recessed and receive bearings journaling the sleeve.
 2. a plurality of bracket members secured radially at spaced peripheral intervals to the drum body, in substantially vertical registration, with the thrust bearing members,
 3. a plurality of adjustable clamp assemblies interconnecting the bearing and bracket members, eacH clamp assembly comprising a. first and second clamp members interconnected for simultaneous rotation and for relative longitudinal movement, b. adjustment means interengaging the first and second clamp members for adjusting one longitudinally relative to the other, c. means interengaging the first and second clamp members one with its associated bearing member and the other with its associated bracket member for rotation relative thereto to move the bearing and bracket members toward and away from each other, and d. flexible connecting means interconnecting each of said bearing-engaging clamp members, whereby adjustment of the clamping pressure by one of said bearing-engaging clamp members equally adjusts the clamping pressure applied by the remaining bearing-engaging clamp members.
 3. The kettledrum of claim 1 wherein the brackets comprise a pair of inverted hook-shaped arms and the bracket engaging means comprises a rod receivable in the hook portions of the arms.
 3. a plurality of adjustable clamp assemblies interconnecting the bearings and brackets, each clamp assembly comprising a. a shaft extending through one of the aligned bearing and bracket pairs, b. a sleeve rotatably and slidably mounted in the bearing, receiving and interlocked with the shaft, c. a first thrust bearing head integral with the upper end of the sleeve, bearing against the thrust bearing, d. flexible drive means interconnecting the sleeves of all of the clamp members, e. bracket engaging means on the lower end of the shaft, f. the sleeve and shaft being rotatable together, g. and the flexible drive means transmitting the torque to the shafts of all of the clamp assemblies, thereby adjusting the pressure applied to the bracket engaging means and correspondingly tensioning the drumhead, h. a second thrust bearing head on the upper end of the shaft, bearing against the first thrust bearing head and operable to adjust selectively the clamping pressure applied to the drumhead in the area immediately adjacent the clamping assembly.
 3. a plurality of adjustable clamp assemblies interconnecting the bearing and bracket members, each clamp assembly comprising a. a shaft threaded at its opposite ends with threads of different speed, b. first adjusting means operatively engaging one threaded end of the shaft with one of the associated bearing and bracket members, c. second adjusting means operatively engaging the other threaded end of the shaft with the other of the associated bearing and bracket members, d. whereby relative rotation of the shaft and first adjusting means effects movement of the associated bearing and bracket members toward and away from each other at one predetermined rate and relative rotation of the shaft and second adjusting means effects movement of the associated bearing and bracket members toward and away from each other at a different predetermined rate, and e. flexible connecting means interconnecting the plurality of adjusting means associated with the faster threads, whereby adjustment of clamping pressure by one of said adjusting means equally adjusts the clamping pressure applied by the remaining ones of said adjusting means.
 4. The kettledrum of claim 1 wherein the sleeve and shaft are keyed together.
 5. The kettledrum of claim 1 wherein the drive means comprise sprockets fixed one to each sleeve and a continuous chain engaging all of the sprockets.
 6. The kettledrum of claim 1 wherein the first thrust bearing head comprises a hollow nut integral with the sleeve and the second thrust bearing head comprises a nut threaded on the shaft and received in a recess in the first thrust bearing head.
 7. The kettledrum of claim 1 including tensioning means associated with the flexible drive means, the tensioning means comprising a radially slotted block secured to the peripheral surface of the body, a slide mounted in the slot, screw means threaded through the bracket and block for adjusting the position of the block in the slide, a vertical shaft mounted on the block and an idler wheel mounted for free rotation on the shaft and engaging the flexible drive means.
 8. The kettledrum of claim 1 including a calibrated position scale secured to the body parallel to the flexible drive means and adjacent thereto and pointer means fixed to the flexible drive means in operative position relative to the scale.
 9. The kettledrum of claim 1 wherein selected ones of the brackets are provided with support surfaces and including drum support legs engaging such surfaces, thereby freely supporting the drum.
 10. The kettledrum of claim 9 wherein the bracket comprises a pair of parallel spaced-apart arms, the undersurfaces of which provide the support surfaces and wherein the leg is insertable between the arms and provided with a cross pin engaging the support surfaces thereof.
 11. The kettledrum of claim 1 wherein the upper and lower ends of the shaft have slow-pitched and fast-pitched threads, respectively, and wherein the second thrust bearing head comprises a nut threaded on the upper end of the shaft and the bracket engaging means comprises a nut threaded on the lower end of the shaft.
 12. A kettledrum comprising a. a hollow substantially hemispherical body, b. hoop means supporting a taut head over the open end of the body, c. counterhoop means in operative engagement with the hoop means, d. head tensioning means interengaging the body and counterhoop means, and E. drum support means comprising
 13. The kettledrum of claim 12 wherein each bracket comprises a pair of parallel spaced arms receiving between them the upper end of the associated leg, and wherein the leg is provided with a cross pin engaging and supporting the arm in bearing relation.
 14. A kettledrum comprising a. a hollow, substantially hemispherical body, b. hoop means supporting a taut head over the open end of the body, c. counterhoop means in operative engagement with the hoop means, and d. head tensioning means interengaging the body and the counterhoop means and comprising:
 15. The kettledrum of claim 14 wherein a. the first adjusting means comprises a threaded nut on the faster thread of the shaft and engaging the bracket member, and a sleeve mounted on the shaft for simultaneous rotation therewith and for relative longitudinal movement of said shaft and sleeve, the sleeve engaging the bearing member, b. the second adjusting means comprises a threaded nut on the slower thread of the shaft and engaging the sleeve, and c. the flexible connecting means is secured to the sleeve, d. whereby rotation of the plurality of sleeves and shafts effects simultaneous movement of the associated bearing and bracket members toward and away from each other at a predetermined rate and rotation of each second adjusting nut relative to its associated shaft effects movement of the associated bearing and bracket members toward and away from each other at a slower rate.
 16. A kettledrum comprising a. a hollow substantially hemispherical body, b. hoop means supporting a taut head over the open end of the body, c. counterhoop means in operative engagement with the hoop means, and d. head tensioning means interengaging the body and the counterhoop means and comprising: 